The purpose of the study is to 1) determine the relative antiviral activity of nucleoside analog regimens as determined to HIV-1 plasma associated RNA in subjects with relatively early HIV-1 infection and CD4 cell counts 550; 2) to determine in these subjects whether the sequence of administration of the reverse transcriptase inhibitors, ZDV and ddI, affects antiviral activity as measured by HIV-1 plasma associated RNA; and 3) to determine in these subjects the relative safety and tolerance of these regimens.